This all means that, statistically speaking, you are probably working alongside someone who is struggling with a metal illness. Unfortunately, there is still a stigma surrounding mental illness, which is why so many conditions go untreated.

Cornell University professor Phyllis Gabriel told the WSJ that "the burden of mental disorders on health and productivity throughout the world has long been profoundly underestimated … Mental health problems strongly influence employee performance, rates of illness, absenteeism, accidents and staff turnover."

The only way we'll begin solving this problem is if employers start addressing it openly in the workplace — by offering treatment hotlines or more generous leave packages. But that's not an easy task.